This invention relates generally to an apparatus for mounting a lamp on a reflector of a vehicle headlight, the apparatus defining an opening for receiving the lamp and a surface facing opposite a mounting direction of the lamp, there being three support points formed by the surface for a lamp socket, which points define a perimeter triangle, with one of the support points being arranged to correspond to a positioning tab extending radially outwardly from the socket, the positioning tab being seated in a recess, and the apparatus having a spring holding element with which a side of the socket, diametrically opposite the positioning tab relative to the lamp axis, can be pressed against a fixing element.
Such an apparatus for arranging a lamp on a reflector of a vehicle headlight is disclosed in german Gebrauchsmuster 91 04 169. A lamp is mounted in a ring-shaped lamp carrier constructed of resinous plastic. The lamp carrier is attached on a rear side of a reflector constructed of sheet metal and extends about an opening in the reflector. A bulb having a lamp filament therein is extendable through the opening of the reflector and a flange which surrounds the rest of the socket is seated against a surface facing opposite to a mounting direction of the lamp. Contact of the socket flange with the surface occurs at three support points which define the points of an equilateral triangle, with a lamp axis extending approximate through a center of gravity thereof. One of the three support points corresponds to a positioning tab which extends radially outwardly from the flange as a part thereof. An axis of symmetry, or bisector axis, of the triangle extends through the positioning tab, the support point of the positioning tab and the lamp axis. The positioning tab is formed by two recesses in the flange, each respectively having two sides extending at right angles to one another. Respective ones of the sides defining the recesses are adjacent the positioning tab while the other two sides of the recesses extend on a common line. The opening in the lamp carrier accommodates the socket flange and the positioning tab which is cut out of the socket flange. Further, a spring holding element lies on the axis of symmetry of the triangle formed by the support points extending through the positioning tab, the spring holding element being a spring tongue formed on the lamp carrier with its free end lying, under tension, against a free edge of the positioning tab to press the flange of the socket against a circularly curved shaped interior side of the opening of the lamp carrier with a spring force directed along the axis of symmetry toward the lamp axis. Further, a second spring tongue formed on the lamp carrier serving to attach the lamp can be placed under tension against one of the two small side surfaces of the positioning tab which are parallel to one another and to the axis of symmetry. In this manner, the exact angular position of the lamp is determined. It is, in this regard, disadvantageous that two spring tongues are formed on the lamp carrier for determining the radial position and the angular position of the lamp and that an interior surface forming an opening in the lamp carrier is adapted for the exterior surface shape of the flange of the socket having the positioning tab. Further, an additional spring holding element is necessary to attach the lamp in a direction of the lamp axis, which can be a holding spring, for example, for pressing the flange of the socket against the support surface of the lamp carrier. Further, an exact position of the filament of the lamp relative to the reflection surface of the reflector is also not certain, even when the lamp is properly arranged on the lamp carrier, because the lamp carrier is a separate part and must still be arranged relative to the reflection surface of the reflector.
In german patent publication 28 53 227 A1 a vehicle headlight is disclosed with an apparatus in which a lamp is attachable in an opening of a separate lamp carrier by a single spring holding element, both radially and axially. The spring holding element is a bowed metal strip spring of which a free end portion lies at an edge of a socket plate and presses this edge of the socket plate axially as well as radially. So that a side of the socket plate opposite the spring holding element does not rise up from its support surface, it is, at this side, shoved into a radially open recess of the lamp carrier. This does not assure a rattle free seating of the lamp on the lamp carrier. Further, it is not possible to align the separate lamp carrier exactly relative to a reflection surface of a reflector.
An apparatus of a vehicle headlight disclosed in german patent publication 39 33 347 A1 has a U-shaped bent holding wire spring with which a lamp is attached radially as well as axially in an opening of a reflector. The holding spring's two legs span a socket of the lamp and press it axially, with both legs, against a support surface of the reflector. Between a pivoting position of the holding spring and a cylindrical socket portion both legs have a bend which reduces their spacing from one another. One respective side of each of the bends of the two legs lies against the cylindrical socket portion of the lamp and presses away from the pivoting position of the holding spring, and thereby in the direction in the length extension of the respective leg. The bending of both legs must always have a very exact tolerance so that it can be assured that both legs press against the cylindrical socket of the lamp, because otherwise the lamp will be urged in an undesired radial direction.
It is an object of this invention to provide an apparatus for mounting a lamp on a reflector of a vehicle headlight of the type described in the introductory paragraph above with which the lamp is sufficiently strongly held by a single spring holding element axially and radially relative to a lamp axis, with such a holding being possible with only a single engagement point between the spring holding element and the socket of the lamp so that the holding spring and its attaching elements need not have exact tolerances.